A server is usually held in a tray structure, and sliding rails are mounted on both sides of the tray structure for protecting the server and benefiting the server to move. With the daily increase of various applications, the size of the server is frequently changed in accordance with different requirements, and thus the server is much heavier than ever. When the size of the receiver is changed (such as from 20 inches to 24 inches), the old tray can be used no longer, and another tray has to be used instead to hold the new sever. When the server has been used for a certain period of time, the siding rails located on both sides of the tray will be deformed, and particularly for holding an even heavier server (such as in 5U specification), the conventional tray is not sustainable, and has to be replaced frequently, thus not only causing a lot of inconvenience to users, but also wasting quite a lot of money.
Since the conventional server tray structure has the difficulty of sustaining a heavy server, and cannot satisfy the needs of changing the server's size, the server tray has to be replaced quite often.
Hence, there is a need to develop an extendable tray structure for effectively adjusting the length of the tray structure for receiving servers with various sizes; reinforcing the strength of the tray structure, so as to sustain heavier servers.